It's typical for scores to drop a little from the first diagnostic to the second PT, largely because the second time around you are no longer trusting your gut instincts and instead doing a lot of thinking and analyzing and applying strategies that you aren't yet fully comfortable with and which you may be applying in cases where they are not appropriate. Things tend to get better a few PTs down the road, when the new skills and strategies starting working in concert with your instincts instead of supplanting them.
It's also normal to see fluctuations throughout your practice as different tests have different concentrations of concepts that are, for you, easier or harder, relatively speaking. If you struggle with Flaw questions, you'll perhaps do worse on a test with 9 of them than on one with 5 of them, right? The key is to use those experiences to identify those weak area and build them up so that you are less prone to large fluctuations based on the chance makeup of your particular test. For more on this, check out this blog post:
https://blog.powerscore.com/lsat/bid/31 ... SAT-Casino
As to the drop that some people get on the real test compared to their best, or their most recent, PT, it varies. Some folks go up (and I am seeing a lot of posts in various forums about that happening on the June test this year)! Some go down, some stay about the same. It can vary, a lot. What you can do about it is practice, practice, practice, and do so in ways that minimize the differences between practice and the real thing, so that come test day there are no surprises and everything feels like you've done it all before. Test anxiety is a real factor, so do what you can to reduce that anxiety and you may not see any drop at all!
Adam M. Tyson
PowerScore LSAT, GRE, ACT and SAT Instructor
Follow me on Twitter at
https://twitter.com/LSATadam